President Obama’s 2016 fiscal year budget includes a proposal to place a cap on the amount of money people can contribute to their tax-qualified retirement accounts, including their IRAs, 401(k) accounts and private pensions. Unlike other bad ideas he has suggested recently (taxing 529 college savings accounts, for example), this idea has not yet been walked back.

Why has the president shown no signs of backing down on his proposal to limit how much workers can contribute to the accounts they will no doubt depend on for necessary income during retirement? Perhaps it is because he has received very little blowback on the idea, thanks to the widely held belief that policies like this are designed to only hurt the wealthiest Americans. However, that belief is incorrect. If a policy like this materializes, it would actually hurt the middle class more than anyone else. Here’s how.

The president’s proposal would place the cap on these tax-qualified retirement accounts at $3.4 million for a married couple, so that retirement account income will stay below $210,000 per year – as if $210,000 per year equals “rich.” But why that amount? According to information posted on WhiteHouse.gov, $210,000 is the amount of annual income that could be expected or derived from a $3.4 million retirement account.

Before I go any further, I’ll say this: That figure is not accurate, even according to the most generous financial planning guidelines. Most advisers recommend withdrawing no more than 4 percent per year from a retirement account; by the White House calculation, a $210,000 annual income from a $3.4 million retirement account means the couple is withdrawing a very risky 6.2 percent per year. That will almost surely result in them running out of money before they die.

What the president’s number crunchers don’t realize is that the withdrawal rate is far more important than the portfolio amount, and that the more commonly recommended annual withdrawal rate of 4 percent will result in a yearly income of just $136,000 – again, only if you have $3.4 million in your portfolio.

But what if a couple has a more realistic amount in retirement savings, like the current average 401(k) balance of $91,300? If they withdraw the White House’s 6.2 percent per year from a $91,300 account, that account gives them $5,660.60 per year in retirement income. If they withdraw the recommended 4 percent per year, that account only gives them $3,652 in retirement income. Either way, there’s a 61 percent failure rate – meaning, a 61 percent chance they will run out of money from the account before they die. It’s a recipe for running out of money.

Advisers who understand the risk would suggest no more than 3.5 percent withdrawal rate, which gives them $3,195 in retirement income from the account but has a failure rate of only 3 percent. These are not my estimations; this is using the Vanguard retirement nest egg calculator, a reputable tool for financial professionals. That is how the president’s proposed limits on retirement account contributions, if they ever materialize, will inevitably hurt the middle class.

Just like Social Security before them, IRA and 401(k) accounts are subject to rule changes that the government assured us wouldn’t happen. Decades ago, Americans believed their Social Security accounts had minimal tax implications – and in 2015, as much as 85 percent of Social Security income can be taxed. We were introduced to 401(k) accounts in 1978 believing they were a tax-favored alternative to living on Social Security, and now the president wants to make it harder to live on those, too.

The only way to prevent his proposal from going any further is political pressure from both sides of the aisle. It worked when he proposed taxing 529 college savings accounts, and if leaders from both parties get on board, it can also work to prevent this.

Kraig Strom, CFP®, ChFC® is a retirement income planner at Team Financial Partners in Corona. His articles can be read at PersonalPensionFormulation.com.